Nowadays, liquid foods of the cooking oil, or edible oil type are mostly packed and transported in finished consumer packages of a single-use disposable nature. Edible oils constitute one group of particularly perishable foods which require good chemical, as well as mechanical properties of the packaging container in order to be able to be stored during a lengthy period of time with freshness qualities which are retained or insignificantly diminished. The packaging material in these so-called single use packages therefore most generally consists of a plurality of mutually laminated layers of material which together give the package its requisite product protection properties.
A prior art packaging laminate which is often employed in single-use packages for edible oils and similar perishable food products includes a core layer of paper or paperboard which imparts to the package mechanical strength and configurational stability, and outer layers of plastic, preferably polyethylene, which give the package the requisite tightness properties against liquids. Moreover, the outer layers of plastic make the packaging laminate heat-sealable or fusible in such a manner that mutually facing plastic layers can easily be sealed to one another by surface fusion, for the formation of mechanically strong, liquid-tight sealing joints or seams during the packaging production process. Moreover, such good product protection requires that the package is oxygen gas tight and fat resistant and, to achieve these additional protective properties, it has hitherto been common to modify, by chemical means, the paper or paperboard layer of the packaging laminate by impregnation with an organic fluorine compound which makes the packaging laminate fat resistant and almost impermeable to oxygen gas.
A packaging laminate which employs the above-described chemically modified paper or paperboard layer suffers from serious environmental drawbacks because of the organic fluorine compound which, for example on the incineration of used packages, can create toxic organic combustion products and which, on production of the modified paper or paperboard material, often requires organic solvents of types which are undesirable from the public health point of view.